1. Field of the Invention
The present invention relates to monitor having a supplemental printed circuit board and, more specifically, to a video monitor having a mounting structure for engaging a supplemental printed circuit board package while directly interfacing the supplemental printed circuit board with a main printed circuit board.
2. Background Art
A monitor is generally constructed using a stand and a chassis that is assembled using a front cover and a rear cover. The chassis typically contains a cathode ray tube and a printed circuit board. The increasing performance demands for display devices, resulting from widespread use of multi-media applications in conjunction with a personal computer, has led to the development of various techniques to increase the overall quality of display devices. One method of enhancing monitor performance has necessitated supplementation of the main printed circuit board with additional supplemental printed circuit boards. Generally, the positioning of a supplemental printed circuit board that is used with a monitor is determined by both the size of the supplemental printed circuit board and position relative to the size of the screen of the cathode ray tube. In a monitor that uses a large cathode ray tube, the volume of the monitor is too large to accept attachment of a supplemental printed circuit board to the cathode ray tube itself. In monitors that use a small cathode ray tube, the weight of the cathode ray tube is low enough to allow the supplemental printed circuit board to be mounted onto the cathode ray tube. One method used in monitors that have large cathode ray tubes, a cathode ray tube with a screen of more than twenty inches, is to attach the supplemental printed circuit boards to the main printed circuit board of the monitor.
The chassis of a large monitor may be constructed using a front cover, a rear cover, and a bottom cover. A second bracket may be installed on the front cover, and the second bracket may also be used to support the cathode ray tube. The front portion of a first bracket is fixed to the second bracket by using a fastener. A main printed circuit board that supports various electronic components is installed on the first bracket. A rear printed circuit board is coupled to the electron gun of the cathode ray tube. Another supplemental printed circuit board may be located separately from the rear printed circuit board that is installed on the main printed circuit board. This supplemental printed circuit board is installed above the main printed circuit board within a front shield and a rear shield. The supplemental printed circuit board is connected via a cable to the rear printed circuit board and the main printed circuit board. The shields prevent the leakage of electromagnetic waves. The front shield, the supplemental printed circuit board, and the rear shield form an integral package unit. Hereinafter, the combination of the front shield, the supplemental printed circuit board, and the rear shield will be referred to as a "supplemental printed circuit board package". Within the supplemental printed circuit board package, there is a space between the front and rear shields that accommodates the electronic components of the supplemental printed circuit board. Leg portions extend downwardly from the lower side edges of the front shield and are fixed to the first bracket by fasteners such as a bolt and a washer. The bolt is fastened into a screw hole in the leg portion after passing through a cut-off groove, while the washer is coupled to the bolt. Then, when the shield is positioned on the main printed circuit board, the bolt passes through the cut-off groove of the first bracket and is completely fastened into the screw hole in the leg portion. Thus, the front shield fixedly coupled to the first bracket.
We have found one drawback, however, is that the leg portions of the shield a coupled to the rear portions of the first bracket by a another fastener. Thus, the upper portion of the shield projects further upward to avoid having the supplemental printed circuit board package interfere with the operation of the cathode ray tube that is installed on the second bracket. Furthermore, the chassis that accommodates the cathode ray tube and the shield has to have a sufficient space to properly house all of the various components. As such, the total height of the monitor has had to be increased, thus requiring an increase in the overall size of the monitor.
Furthermore, an additional drawback of this supplemental printed circuit board mounting technique is that only the lower two edges of the supplemental printed circuit board package are fixed. This allows the supplemental printed circuit board package to be rotated when even a small force is imposed on the package. This however can lead to unexpected damage to or a reduction in the performance of the monitor. Additionally, the supplemental printed circuit board package is connected to the main printed circuit board via a cable, thus necessitating an increased number of steps to complete the assembly process and an increase in the complication of the peripheral structure. As such, we believe that it may be possible to improve on the art of the mounting of supplemental printed circuit boards by providing a supplemental printed circuit board package that can be directly attached to a main printed circuit board, that does not rotate when a force is applied to the package, that does not increase the manufacturing complexity by requiring that a cable be used to connect the supplemental printed circuit board to the main printed circuit board, and that does not require that the size of the monitor chassis be increased.